A new species, Gomphosinica selincuoensis sp. nov., is described from Lake Selincuo, North Tibet, China. This taxon is clearly different from the other species in genus Gomphosinica, with a distinctly protracted, rostrate headpole, relatively higher striae density, and distinctive areolae arrangement within the striae. Striae have areolae mostly in 3 rows, but there are places near the central portion of the valve and at footpole where there are only 2 rows of areolae per stria. Characteristics of this taxon, as observed in light and scanning electron microscopy, support its systematic placement in the genus Gomphosinica. This new species is compared with similar species in Gomphosinica from China and North America, and the biogeographic distribution of the genus is discussed.